LibCore: Return ErrorOr<pid_t> and support arguments in Process::spawn

This makes the wrapper more like the rest in LibCore, and also
removes the annoying limitation of not supporting arguments.

There are three overloads one for String, char const *, and StringView
argument lists. As long as there are <= 10 arguments the argv list
will be allocated inline, otherwise on the heap.

2 files changed, 63 insertions, 12 deletions

diff --git a/Userland/Libraries/LibCore/Process.cpp b/Userland/Libraries/LibCore/Process.cpp
index efdf3909e7..afa5fb1a3a 100644
--- a/Userland/Libraries/LibCore/Process.cpp
+++ b/Userland/Libraries/LibCore/Process.cpp
@@ -1,11 +1,14 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <AK/String.h>
+#include <AK/Vector.h>
 #include <LibCore/Process.h>
+#include <LibCore/System.h>
 #include <errno.h>
 #include <spawn.h>
 
@@ -17,21 +20,65 @@ extern char** environ;
 
 namespace Core {
 
-pid_t Process::spawn(StringView path)
-{
-    String path_string = path;
+struct ArgvList {
+    String m_path;
+    Vector<char const*, 10> m_argv;
+
+    ArgvList(String path, size_t size)
+        : m_path { path }
+    {
+        m_argv.ensure_capacity(size + 2);
+        m_argv.append(m_path.characters());
+    }
+
+    void append(char const* arg)
+    {
+        m_argv.append(arg);
+    }
+
+    Span<char const*> get()
+    {
+        if (m_argv.is_empty() || m_argv.last() != nullptr)
+            m_argv.append(nullptr);
+        return m_argv;
+    }
 
-    pid_t pid;
-    char const* argv[] = { path_string.characters(), nullptr };
-    if ((errno = posix_spawn(&pid, path_string.characters(), nullptr, nullptr, const_cast<char**>(argv), environ))) {
-        perror("Process::spawn posix_spawn");
-    } else {
+    ErrorOr<pid_t> spawn()
+    {
+        auto pid = TRY(System::posix_spawn(m_path.characters(), nullptr, nullptr, const_cast<char**>(get().data()), environ));
 #ifdef __serenity__
-        if (disown(pid) < 0)
-            perror("Process::spawn disown");
+        TRY(System::disown(pid));
 #endif
+        return pid;
+    }
+};
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<String const> arguments)
+{
+    ArgvList argv { path, arguments.size() };
+    for (auto const& arg : arguments)
+        argv.append(arg.characters());
+    return argv.spawn();
+}
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<StringView const> arguments)
+{
+    Vector<String> backing_strings;
+    backing_strings.ensure_capacity(arguments.size());
+    ArgvList argv { path, arguments.size() };
+    for (auto const& arg : arguments) {
+        backing_strings.append(arg);
+        argv.append(backing_strings.last().characters());
     }
-    return pid;
+    return argv.spawn();
+}
+
+ErrorOr<pid_t> Process::spawn(StringView path, Span<char const* const> arguments)
+{
+    ArgvList argv { path, arguments.size() };
+    for (auto arg : arguments)
+        argv.append(arg);
+    return argv.spawn();
 }
 
 }
diff --git a/Userland/Libraries/LibCore/Process.h b/Userland/Libraries/LibCore/Process.h
index 79820451e2..89f349d922 100644
--- a/Userland/Libraries/LibCore/Process.h
+++ b/Userland/Libraries/LibCore/Process.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,12 +8,15 @@
 #pragma once
 
 #include <AK/Forward.h>
+#include <AK/Span.h>
 
 namespace Core {
 
 class Process {
 public:
-    static pid_t spawn(StringView path);
+    static ErrorOr<pid_t> spawn(StringView path, Span<String const> arguments);
+    static ErrorOr<pid_t> spawn(StringView path, Span<StringView const> arguments);
+    static ErrorOr<pid_t> spawn(StringView path, Span<char const* const> arguments = {});
 };
 
 }